Conventional fire hydrants have been used for many years as a way in which firefighters can access the water supply of a municipality for use in fighting fires. While such hydrants perform well for their intended use, it has been appreciated of late that the many hydrants connected to a particular water supply could serve as a location at which a person or persons intent on contaminating the water supply could gain access to the water supply.
For example, it is contemplated that, should a person or persons with ill intent wish to introduce into a water supply a contaminant, such as a poisonous, hazardous, or otherwise unsafe material, such a person could do so by way of one of the many hydrants connected to such a water supply. Even if no persons were struck seriously ill, or killed, by the presence of the contaminant in the water supply, once the contaminant was introduced into the water supply, significant time and energy would be required to purge the water supply of the contaminant. In some cases, if a contaminant such as radioactive material were introduced into the water supply, the entire water delivery system (e.g., pipes, pumps, treatment facilities, etc.) may have to be replaced before safe drinking water could be supplied to the municipality.
Systems for preventing just such an event have been proposed, and generally consist of installing a “back pressure” valve in the upper dry barrel of the hydrant to limit or prevent any material from flowing through the hydrant into the water supply. While such systems have been proven at least partially efficacious, they have, to date, included components that are installed within the upper barrel of the hydrant itself. As such, these systems themselves are susceptible to tampering and can be relatively easily rendered ineffective by a person or persons intent on contaminating the water supply by way of a hydrant in which such systems have been installed. In addition, many of these systems are designed for use with new hydrant installations, and are not readily adaptable for retrofitting of existing hydrants.